Electrosynthesis, Characterization and Electrocatalytic Behaviour of Organic-Metal Thin-Films Based on 2,2’-Bithiophene-5-carboxylic Acid and Metal Ions

2,2’-Bithiophene-5-carboxylic acid (BTA) thin-films on platinum (Pt) electrodes were electrochemically prepared in acetonitrile solution containing 0.1 M tetrabutylammonium perchlorate (TBAP) and 0.05 M BTA. These films were complexes with several metal ions such as Cu2+, Ag+ and Co2+. Their structural characteristics were compared with those of powder complexes chemically prepared from BTA and the corresponding metal ion. IR and XPS techniques reveal that the film complexes with metal ions have the same structures as the corresponding powder complexes. The electrocatalytic activity of BTA film-metal ions has been investigated toward ascorbic acid (AA) oxidation and compared to that obtained on a free BTA film. BTA film-metal ions exhibit good catalytic proprieties and better detection of AA than a free BTA film. This new propriety allows these films to be used as electrochemical sensors. This electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.

Synthesis, Crystal Structure and DNA-Binding Property of a Mn(Ⅱ) Complex Based on 5-(Tri-fluoromethyl)pyridine-2-carboxylic Acid

A new complex Mn(Htpc)2(H2O)2(1, Htpc = 5-(trifluoromethyl)pyridine-2-carboxylic acid) has been synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. 1 belongs to triclinic system, space group P■ with a = 5.0885(10), b = 6.5574(13), c = 14.016(3) ?, β = 90.67(3)o, V = 436.34(17) ?3, Z = 1, Dc = 1.793 g·cm-3, μ = 0.855 mm-1, Mr = 471.18, F(000) = 235, the final R = 0.0454 and wR = 0.1134 for 1998 observed reflections with I > 2σ(I). The Mn(Ⅱ) ion is coordinated by two N and two O atoms from two Htpc as well as two O atoms from two coordinated water molecules, forming a 0D motif with distorted octahedral coordinate geometry. The adjacent 0D units are linked into 1D chains through hydrogen bond O(1W)–H(1 WB)···O(2), and via the O(1 W)–H(1 WA)···O(1) hydrogen bond the neighboring 1D chains are connected into a 2D supramolecular layer. Moreover, the interactions between the ligand and its complex with CT-DNA were studied by EtBr fluorescence probe, which suggested that these compounds bind to CT-DNA through an intercalation mode. The binding constants were 0.41 and 0.64 for Htpc and complex 1, respectively. It indicates that the interaction between complex 1 and CT-DNA is stronger than Htpc.

Sensitized photooxygenation^+——VI. Kinetic studies on the singlet oxygenation of 6-ethyl-3,4-dihydro-2H-pyran-5-carboxylic acid ethyl ester and 6-isopropyl-3,4-dihydro-2H-pyran-5-carboxylic acid ethyl ester

Kinetic studies of the singlet oxygenation of the title compounds were performed accord- ing to Monroe's method. The reaction rate increases with temperature decreasing, leading to a ne- gative activation enthalpy and a large negative activation entropy. These data are interpreted as the evidence for the intermediacy of an exciplex. The solvent effect on the reaction rate suggests that the “dioxetane” path involves a transition state or an intermediate with significant zwitterionic character. The electronic effect of the substituent is obvious, with electron-withdrawing substituent retarding the reaction and electron-donating substituent increasing the reaction rate. However, steric bulkiness at the 6-position does not play an important role in the reaction rate.

Synthesis, Crystal Structure and Thermal Stability of the Coordination Polymer [Co(2-mpac)_2(py)·4H_2O)]_n

A new coordination polymer with the formula of [Co（2-mpac）2（py）·4H2O）]n （1, 2-mpac = 5-methyl-2-pyrazinecarboxylic acid, py = pyrazine） has been synthesized through hydrothermal synthesis and structurally characterized by X-ray single-crystal diffraction method. 1 exhibits a 3D supramolecular network. Crystal data： monoclinic, space group C2/m, a = 15.907（9）, b = 7.104（3）, c = 9.793（5）, β = 95.232（8）o, V = 1102.0（10）3, Z = 2, S = 0.995, the final R = 0.0509, wR = 0.1626 for 1002 observed reflections with （I 〉 2σ（I）） and R = 0.0530, wR = 0.1667 for all data. In addition, elemental analysis, IR and thermalgravimetric analysis are presented.

Urothermal Syntheses of Chiral Zincic Benzotriazole-5-carboxylate Frameworks for Iodine Uptake

So far,the synthesis of chiral framework with achiral organic ligand still faces great challenge.Herein,three new coordinated complexes[Zn(btca)Cl]·DMA·N(CH_(3))_(2)(1),[Zn(btca)(Ac^(-))]·N(CH_(3))_(2)(2)and[Zn(btca)]·H_(2)O(3)(DMA=N,N-dimethylacetamide,btca=benzotriazole-5-carboxylate acid)were synthesized via different methods.Single-crystal X-ray diffraction analysis revealed that compounds 1 and 2 were isostructural and showed achiral layer network with fes topology,and 3 presented a chiral three-dimensional framework with eta topology.The result of this work has demonstrated that urothermal synthesis will be promising means of constructing chiral framework with achiral building block.Compound 3 also displayed an excellent property of iodine uptake.

百尾参化学成分的分离与鉴定

目的研究百尾参Disporum cantoniense的化学成分。方法利用各种色谱技术进行分离,运用现代光谱技术鉴定化合物结构。结果从百尾参中分离得到16个化合物,分别鉴定为马来酸酰亚胺-5-肟(1)、4-methylene-5-oxopyrrolidine-2-carboxylic acid(2)、胸腺嘧啶(3)、腺嘌呤核苷(4)、5′-deoxy-5′-methylamino-adenosine(5)、乙基-α-L-鼠李糖(6)、岩白菜素(7)、4-羟基-2-甲氧基苯基-6-脱氧-α-L-吡喃木糖苷(8)、(-)-表儿茶素(9)、(6R,9R)-roseoside(10)、3-(4-羟基-3,5-二甲氧基苯基)-丙烷-1,2-二醇(11)、3-羟基-5-(p-羟基苯基)-戊酸(12)、1-核糖醇基-2,3-二酮-1,2,3,4-四氢-6,7-二甲基-喹喔啉(13)、(6S,9R)-vomifoliol(14)、3,4-二羟基苯酰甲醇(15)和1,2-二羟基-1-(4-羟基-3,5-二甲基苯基)-乙烷(16)。结论化合物1、2、5~9、12~16为首次从该属植物中分离得到;化合物1、2、5~10、12~16为首次从该植物中分离得到。